Over 400 hypertension-related traits have been measured on 923 individuals in five large families. These families were originally ascertained through single probands with essential hypertension by Dr. Roger Siervogel of Wright State University. DNA has been extracted from stored samples and genotyping for nearly 400 polymorphic genetic markers was completed by the Center for Inherited Disease Research. Because of problems with DNA extraction and limited amplification, polymorphisms could be determined for only about 250 individuals. Therefore, efforts are underway to recontact these families, obtain blood and retype missing individuals to complete the study. IRB approval will be obtained in the coming year to recontact missing individuals. Model-independent linkage analysis will be done to determine if genetic components responsible for variation in each of the hypertension-related traits can be identified and localized in the human genome.